Investigation of Single-pilot Operation Accidents

by Fabio Couto Bonnett, Air Safety Investigator, Embraer Air Safety Department

Fabio graduated in aeronautical engineering in 2005 and has worked in the aviation industry since 2002. He joined Embraer Air Safety Department in 2012 and has worked since then as an Air Safety Investigator in the investigations group, which is responsible to provide technical support for official investigations involving Embraer products according to provisions of ICAO's Annex 13. Fabio is also a certified flight instructor, type rated in the Phenom 300 as pilot-in-command and is the focal point for operational aspects at Embraer Air Safety Department headquarters in Brazil.

Introduction

A recent study(1), comparing accidents involving one-pilot versus two-pilot business jet

operations in a 37-year period, revealed that 37 percent of the analyzed accidents involved

jets crewed by one-pilot versus 63 percent with jets crewed by two pilots. Even though the

number of two-pilot accidents was higher, single-pilot ones resulted in more fatal crashes.

Embraer has assisted investigation authorities in several events involving single-pilot

operations and valuable lessons were learned from these events in terms of training,

publications, as well as investigation procedures and safety factors involved once single-pilot

operations have peculiar characteristics when compared to two-pilot operations. Embraer

has looked deeper into operational aspects present in the occurrences with the objective to

identify trends, develop improvements and enhance the investigation process.

For a thorough understanding, this paper presents the concept of single-pilot operation, its

certification requirements, limitations and the profiles of the pilots who usually crew aircraft in

single-pilot operations . This paper aims to share Embraer's experience gathered from years

supporting investigations of this type of occurrence worldwide, with the purpose to provide

investigators with important aspects to be observed throughout the investigation of

occurrences involving single-pilot operations, as well as to point-out the importance of turning

the lessons learned from these occurrences into assertive and feasible recommendations.

Single-pilot jets - background

Most business jets are certified in the transport category because they have maximum

certified takeoff weights greater than 12,500 pounds (5,670 kilograms), the threshold

between large and small aircraft, certified under part 25 and part 23 rules respectively(2) (3).

One of the various differences in the certification rules between small and large aircraft is the

requirement for at least two pilots in the large transport category airplane(4).

In almost every area of certification, the standards for jets have been more rigorous than the

ones for turboprop airplanes. One of those standards had been the requirement for two

pilots, which remained in force until 1977 when Cessna won approval for single-pilot

operation of its Citation I-SP with the intent to market it against small twin turboprops(5). Since

then, other small jets were also certified to be crewed by one pilot such as the Eclipse 500,

Mustang, Premier I, Phenom 100, Phenom 300, Honda Jet and some Citation versions. Most

single-pilot jets are very light jets (VLJ), which fall under the small aircraft category once they

usually have maximum take-off weights under 10,000 pounds (4,535 kilograms).

For many years, cockpits of aircraft certified under part 23 requirements were simple in

design and used instruments and systems that were also similar in operation. This made it

easy for pilots to transition safely from one part 23 aircraft to another. However, because of

the continuous growth of modern technology and the reduced cost of electronic components,

newer and more complex integrated avionics are increasingly being installed in part 23

airplanes. These new systems have changed the appearance, operation, as well as man-

machine interface.

14 CFR part 23, §23.1523 establishes the criteria for determining the minimum flight crew

and in order to have an aircraft certified as single-pilot, some aspects such as workload, pilot

interface with the cockpit equipment and degree of automation must be consistent with

having only one pilot onboard the aircraft. The following are some known workload factors

considered significant when analyzing and demonstrating workload for minimum flight crew

determination(6):

- The impact of basic airplane flight characteristics on stability and ease of flight path control.

- The accessibility, ease, and simplicity of operation of all necessary flight, power, and

equipment controls, including emergency fuel shutoff valves, electrical controls, electronic

controls, pressurization system controls, and engine controls.

- The accessibility and conspicuity of all necessary instruments and failure warning devices

such as fire warning, electrical system malfunction, and other failure or caution indicators.

The extent to which such instruments or devices direct the proper corrective action is also

considered.

- The complexity and difficulty of operation of the fuel system, with particular consideration

given to the required fuel management schedule required by e.g. structural, or other

airworthiness considerations. Additionally, the ability of each engine to operate continuously

from a single tank or source that is automatically replenished from other tanks if the total fuel

supply is stored in more than one tank.

- The degree and duration of concentrated mental and physical effort involved in normal

operation and in diagnosing and coping with malfunctions and emergencies, including

accomplishment of checklist, and location and accessibility of switches and valves.

- The extent of required monitoring of the fuel, hydraulic, pressurization,

After the certification authority determines that the proposed design allows the pilot to

physically manage the cockpit from the left seat, actual flight testing will determine if the

airplane can be approved for single-pilot operation. The results from these flights base the

Flight Standardization Board (FSB) Report, specifying training, checking and currency

requirements to flight crew operating the referred aircraft (7).

In this case, it is the airplane that is approved for single-pilot flying, not the pilot. Therefore a

training program must be developed by the aircraft manufacturer and it needs to be approved

by the certification authorities in accordance to the FSB report.

From the owner pilot perspective, single-pilot operation is all about flexibility and it is

understandable why most of them prefer to fly their business jets without a copilot. The

convenience of taking off when you want, staying there as long as you want, and all other

aspects of operating your own aircraft are at least a little more complicated when you need

an extra pilot.

Single-pilot Operation - Human performance

In aviation, the decision making process has been an area of interest for investigators and

aviation safety professionals. The occurrence of errors in the decision making process is

usually related to the aviation context itself which is surrounded by quick-changing scenarios,

as well as challenging factors that may compromise crew performance, such as complexity

of systems and level of automation.

Workload is defined as the relationship between an individual's capacity to perform a task

(mental and/or physical), and the level of system and situational demands associated with

the performance of that task. The basic notion is related to the differences between the

amount of resources available in the operator (human being) and the amount of resources

demanded by the task. Tasks that demand much of the human resources are considered

high workload tasks. Conversely, tasks that demand little of the human resources (capacity)

are considered low workload tasks.(4)

Human error is often related to workload, and there is usually a positive correlation between

excessive workload and the occurrence of errors. It should be noted that errors could also be

associated with low workload. Levels of workload that are too low are often found in fully

automated systems where the operator serves largely as a monitor of the automated

processes. In these cases the operator/pilot may become inattentive and/or bored, and this

situation is generally referred to as task underload. At the opposite extreme, levels of

workload that are too high often cause the pilot to miss important information, fail to perform

tasks, make errors or engage in task shedding in an attempt to reduce workload.

The single-pilot operation introduces a different dynamics in the cockpit when compared to a

dual-crew operation. The decision making process and the overall management of the flight

lays on the solo pilot and, therefore, the automation plays a very important role in reducing

the workload throughout the flight. Even though aircraft systems are known to be very

reliable, they are not equipped with airmanship as humans are and, therefore, single-pilot

operation increases the need for threat and error management, adequate training, planning

and decision making.

Since a second pilot is not available to support the operation, the solo pilot is responsible for

the flight planning, systems monitoring, flying the aircraft, communication and self-evaluation

that provides the necessary feedback for further performance improvement. When combined,

these actions demand a significant cognitive and psychomotor workload(8),which varies

throughout the operation depending on the flight phase, weather, terrain, infrastructure,

among other factors.

Psychomotor skills, related to the ability to control the aircraft, are specially demanded on

takeoffs, landings and emergency situations and are less demanded during cruise phase. On

the other hand, cognitive skills are demanded throughout the entire flight and are related to

the satisfactory conclusion of the operation in each flight phase, operation of the different

systems, performance assessments, reading and execution of emergency procedures,

emotion control, among others(9).

During normal operation, the workload can be generally foreseen on each phase of the flight,

allowing the pilot to anticipate the actions and reduce workload. On emergency situations,

exceptional events require specific actions from the pilot (immediate or not). The degree of

complexity associated to an emergency will determine the urgency and sequence of actions

to be taken by the pilot. Generally, these situations increase the pilot's workload who shall

keep focused on managing the flight while applies the necessary measures to manage the

emergency.

The workload on normal and abnormal operations is taken into account when an aircraft is

certified as single-pilot and the absence of one crewmember in the cockpit is a characteristic

of this kind of operation and not a limiting factor for a good operational performance(6).

Single-pilot Operation - History of occurrences

A 2015 analysis(1) comparing accidents involving one-pilot versus two-pilot business jet

operations from 1977 through 2014 revealed that, from a statistics standpoint, there is only a

slight safety advantage to having a multiple cockpit crew in single-pilot jets. The analysis

examined 107 accidents, 40 of which were in jets piloted by a one-pilot crew versus 67

accidents in jets crewed by two pilots. Although there were more two-pilot accidents, half of

the single-pilot accidents were fatal crashes compared with 45 percent of two-pilot accidents.

Figure 1 shows the statistics by types of accidents.

Figure 1 - AIN Statistics: Accident totals by number of pilots

On August 2nd, 1979 a Citation 501 crashed in

Akron, Ohio, flown by the New York Yankees

catcher Thurman Munson. The accident got a very

extensive media coverage but one very important

aspect was not reported by them: This was the first

fatal crash involving a single-pilot certified light-jet.

According to the NTSB final report, the probable

cause of the accident was the pilot's failure to follow

the appropriate checklist and to recognize the need

for, and to take action to maintain sufficient airspeed

to prevent a stall into the ground during an

attempted landing(10).

This accident, followed by several others throughout

the years, raised questions about the safety of

single-pilot operations, whether they are inherently

less safe when compared to a two-pilot operation.

The fact is that there are no evidences that this

accident could have been avoided if there had been

another pilot sitting on the right seat.

Out of the 107 accidents with business jets certified for single-pilot operation, 67 were

crewed by two qualified pilots while 40 were crewed by one qualified pilot. Going deeper into

the numbers, approximately 45% of the two-pilot accidents resulted in 102 casualties while

50% of the single-pilot accidents resulted in 58 casualties. Even though the percentages of

fatal accidents are similar, the numbers show that more people perished in two-pilot

accidents from 1977 to 2014.

The most frequent type of accident was runway excursion on landing and most of them were

survivable. Runway excursions with more serious results typically happened due to the

crew's inadequate decision-making process, such as electing to continue on an unstable

approach and land(1). The study revealed that 26 runway excursions happened on two-pilot

operations versus 12 on single-pilot operations, more than double.

The study showed that the number of accidents are proportional to the fleet size. Therefore,

the fleet that has produced more aircraft is likely to have more accidents, statistically-wise.

Every flight, single-pilot or not, has hazards and some level of risk associated with it. It is

critical that operators and pilots are able to differentiate, in advance, between a low risk flight

and a high risk flight, and then establish an assessment process and develop risk mitigation

strategies to address flights throughout that range. A risk assessment tool allows pilots to

identify the risk profile of a flight in its planning stages.

Many corporate operators may have the perception that having two qualified pilots onboard

the aircraft reduces the risk level and provides the operation with a higher level of safety than

having just one pilot. Even though the numbers presented herein do not support this

perception, many operators choose to limit their single-pilot operations according to the

profile of the mission as a way to mitigate the risks in specific operations.

Single-pilot Operation accidents - The investigation

After the investigation authority has been notified of an accident, it is likely that the go-team

will be launched to the crash site. It is important to remember that a single-pilot accident is no

different than any other accident and all necessary precautions must be taken to ensure the

safety of the group during the on-site activities. Such precautions include a thorough risk

assessment prior to deployment of the team, use of appropriate safety equipment, health

precautions, among others.

The following topics present suggested lines of investigation for a single-pilot accident, based

on Embraer's experience with this kind of event throughout the years. The events described

herein are based on final reports from accident investigations worldwide.

Activities at the crash site

Recorders Most very light jets (VLJs) are equipped with a cockpit voice recorder (CVR) unit and it is

imperative that the recorded audio is not overwritten after the accident. Since many

accidents are survivable and the damage to the aircraft are usually not very extent, it is

not uncommon for the aircraft to be powered-up after the event. Therefore, whenever

feasible, upon notification of the accident, the investigator shall instruct the operator of

the aircraft to pull the associated circuit breaker and keep the aircraft powered-off so that

the unit is de-energized, preventing the audio from being overwritten. If, for any reason,

this is not feasible, the investigator shall do it immediately upon arrival at the crash site.

Some aircraft may have more than one recording unit, so it is important that all related

circuit breakers are pulled. The Phenom 100 and 300 are equipped with a combined

voice and data recorder installed in the rear section of the aircraft. The Phenom 300 has

an additional FDR unit installed in the front section of the aircraft (optional) and there are

different circuit breakers for each unit.

Central Maintenance Computer (CMC) The aircraft's central maintenance computer stores several important information.

Aircraft with advanced avionics presents advisory, caution and warning messages

depending of the type of malfunction. These messages are logged in the CMC's memory

and can be downloaded for further analysis if the unit is not damaged. If it is safe to

power-up the aircraft, the investigator should download the data on-site. In most cases,

the unit is removed from the aircraft and preserved for further analysis at the

manufacturer of the component. Embraer Phenom 100 and 300's CMC records, among

other parameters, the latitude, longitude and groundspeed of the aircraft upon take-off

and landing and they are able to transmit the CMC logs to an Embraer server every time

the aircraft lands, thus allowing investigators to quickly determine the touchdown point of

the aircraft within minutes after the accident takes place.

Pictures Just like any other accident, the investigator should not hesitate to take as many pictures

as possible, even if it feels like they will not be of help in the future and, also, remember

to document everything before they are touched or moved. It is not recommended to

delete photos from the camera, so that the file number sequence is not disrupted.

Recording videos can also be a helpful tool to register the condition of certain parts of

the aircraft and the accident environment. Sometimes, time available in the crash site

may be limited and narrated high-definition videos can be a quick and reliable way to

document the crash site.

Cockpit Since most VLJs are not equipped with a FDR unit, cockpit pictures are a very

helpful resource for operational analysis of single-pilot accidents. They will show

the positions of knobs, switches, push-buttons, flap lever, landing gear handle,

emergency parking brake lever, condition of oxygen masks, emergency

equipment, whether a performance data card was filled out for that phase of flight,

etc.

The investigator should also take pictures of the onboard aircraft manuals covers

to register which revision of the manuals the crew was using.

After taking as many pictures as possible in the cockpit, the investigator may want

to try the push-buttons and document their positions since they are very difficult to

be identified by pictures.

Passenger cabin Detailed passenger cabin pictures will show the investigators the conditions of seat

belts, use of emergency exits, use of emergency equipment, safety card

information, etc. This will help the investigator gather data for the survival factors

investigation.

External pictures External pictures may also be a source of information for further questions about

the aircraft damage. It is very important to take pictures of the wings, flap panels

positions, flap actuators, flight control surfaces, trim tabs, engines general

conditions (fan blades, cowling, oil level) pitot tubes, angle of attack vanes, landing

gears general conditions (including tires, wheels and brakes), general condition of

doors and emergency exits and any other items the investigator finds relevant

Crash site and surroundings As mentioned above, runway excursion is the top one type of occurrence with

VLJs. It is important to document runway conditions (drainage, holes, surface

uniformity), runway markings (touchdown point, braking marks, hydroplaning

marks), runway departure point, impact marks etc.

GPS markings A handheld GPS is very helpful for the investigator to put together a crash site sketch.

Using the GPS, the investigator can mark the location of debris, touchdown point,

runway departure point, as well as record individual tire mark tracks throughout the

runway. It is important to remember that, for a better accuracy, all markings must be

done within the hour. In addition to that, it is recommended that the investigator records

a tracking over a known region, such as runway edges, so the recorded markings and

tracks can be adjusted on the map if necessary. Figure 2 shows the green tracking

recorded along the runway edges during the on-site activities further used to calibrate

the position of the tires marks recorded over the runway.

Figure 2 - Recorded GPS tracking along the runway threshold used as reference for

calibration

Lines of investigation Depending on the country, pilots are allowed to get their initial and recurrent training in the

full flight simulator or in the actual aircraft. Most part 91 VLJs crewmembers come from twin-

engine piston and turboprop aircraft and VLJs are usually their first jet experience. They are

usually businessmen and do not fly on a daily or weekly basis.

Most accidents involving VLJ operation are essentially related to operational aspects and the

following factors have been present on the majority of the events that Embraer has analyzed.

Training It is recommended to research the crewmember's training history, back to basic training

at the flight school, to identify possible learning difficulties the pilot might have had in the

past or behavior profiles that could be identified in the accident.

Previous equipment flown by the crewmember An aircraft differs from an automobile where one can drive different models and operate

their systems without major difficulties. Each aircraft has different systems, procedures,

limitations and handling characteristics and it is not uncommon for VLJ pilots, who have

logged hundreds of hours on twin-piston engine or turboprop aircraft to revert to their

previous knowledge on those aircraft and get the procedures mixed in their minds. The

same can happen to pilots who logged thousands of hours on wide-body jets.

In one event, the pilot was monitoring the fuel levels in each wing after takeoff and

noticed a certain difference between those tanks. While still climbing and without getting

any fuel imbalance CAS messages, the pilot decided to open the fuel transfer valve to

balance the fuel and commanded a turn, which aggravated the imbalance to a point

where one of the wings got really heavy and large aileron trim deflection was necessary

to keep the wings leveled. The pilot requested to turn back and the aircraft landed

uneventfully. During the investigation, while interviewing the pilot, he mentioned that he

opened the cross feed to balance the fuel. However, the aircraft he was flying at the time

of the occurrence did not have a cross feed system, but a gravity fuel transfer system.

The pilot was relatively new to this aircraft type and brought his previous knowledge from

the equipment he had flown for over 5 years prior.

Passenger on the right seat. It is not uncommon for a passenger to seat in the right seat during single-pilot

operations. Based on previous accidents analyses, some of these passengers were

pilots, not type rated in the aircraft, and were assigned operational duties such as

callouts, communications, FMS programming, aircraft configuration and even the landing

itself. Having someone seating in the right seat does not decrease the single-pilot

operation safety itself but if, during critical phases of the flight, the pilot in command is

engaged in extra activities (not expected in single-pilot operations) such as explaining

the functioning of the aircraft systems and monitoring the actions taken by the person

seating in the right, higher cognitive skills might be demanded and may affect the pilot's

capacity to focus on what is relevant to the flying task. In some countries such as Brazil,

the person occupying the right seat may not operate the aircraft or its systems unless

this person is fully type rated in the aircraft.

In one event, when the aircraft was still on the ground before takeoff, the crew received

a crew alerting system (CAS) message, indicating a brake fail condition which they

attempted to reset, unsuccessfully. They decided to continue their departure and the

CAS message stayed active for the entire flight. There was a pilot type rated in the

aircraft occupying the left seat and another pilot on the right seat who was not type rated

in the aircraft. The pilot on the left was flying the airplane for most of the flight and

conducted a GPS approach. Just before landing the pilot on the right took over and, after

touchdown, discovered that they had no brakes. The airplane began skidding after the

emergency parking brake (EPB) handle was pulled.

In another event, the aircraft overran the runway limits after landing on a water

contaminated runway. The pilot seating on the left was type rated in the aircraft and the

pilot on the right was not. According to the FDR data, the touchdown occurred

approximately 1,700 feet (520 meters) past the runway threshold. As per the CVR, the

pilot seating on the right, who was not type rated in the aircraft, landed the aircraft with

verbal assistance from the pilot on the left.

Motivation Motivation is a drive that causes one to act or behave in certain ways. The word

"motivation" itself is neutral in meaning and may have positive or negative connotations

such as making safe decisions or taking risks. Human error is context dependant and is

usually aggravated by personal characteristics such as experience, self confidence,

pride, etc. This combination may lead individuals to ignore evidences in favor of anything

they disagree with and give more weight to information that confirms what they know to

be true. Such tendency is known as confirmation bias. Owner pilots are usually

successful businessmen who are used to taking risks in their professional lives and such

personal characteristic is sometimes brought to the cockpit, influencing the pilot's

decision-making process.

In one event, the aircraft experienced a runway excursion after landing on a water-

contaminated runway. Upon takeoff from the origin airport, the weather conditions at the

destination were favorable to a landing under visual flight rules (VFR) but throughout the

flight, weather conditions at the destination started to deteriorate. The pilot reported

difficulties in coordinating clearances with the ATC. The approach would initially be

conducted to the southeast but due to the start of precipitation over the airport, the

runway in use changed. In the meanwhile, in the base leg, with the runway in sight, the

pilot was instructed by the ATC to perform a 360-degree turn to maintain separation from

3 other traffic in the pattern. Precipitation increased over the airport and even though

visibility was reduced, the pilot configured the aircraft for landing, continued with the

approach and ended up skidding off the runway. The pilot reported that he was

motivated to land due to the previous difficulties with ATC and also due to the weather.

He was concerned that if he had to go around, he would not be able to proceed back to

the airport due to the deteriorating weather. The pilot's motivation played a very

important role in his decision-making process, leading him to take unnecessary risks.

Even though this was a single-pilot operation, this was not the case of an owner pilot

operating the aircraft. The pilot was an experienced captain, with over 17,000 hours

logged in the commercial aviation.

Human Stress Stress has been a frequent cause of accidents in aviation. Defining stress is not a simple

task since its causes, also known as stressors, come from different sources.

There are several good definitions of stress, but the following is very interesting: "Stress

is the state of dynamic tension created when you respond to perceived demands and

pressures from outside and from within yourself" (11)

Basically, this definition states that stressors are present in both external and internal

factors. By nature, stressors can be environmental (e.g., temperature, noise, luminosity),

psychosocial (e.g., family, work, friends) and psychological (e.g., health, hunger, well-

being). Stressors cause the human body to have responses that are usually common

and sometimes non-specific ones and the magnitude of the responses are proportional

to the relevance of the stressors to each individual.

Human performance is intimately related to stress level. As stress rises, one's motivation

and attention also rises, causing performance to improve. If the stress level becomes too

high, motivation and attention degrade, leading to a reduced performance.

As mentioned before, owner pilots of VLJs are usually successful businessmen who use

their own aircraft for business. A businessman, tight on schedule and flying himself to an

important business meeting usually brings his expectations, strategies and concerns to

the cockpit, which increases his level of stress, possibly leading him to a scenario of self-

imposed pressure where his performance is likely to be degraded.

Aircraft Performance Performance has been a contributing factor in most single-pilot accidents. Not the

aircraft performance itself but the crew's assessment about it and adherence to the

aircraft limitations and performance numbers. The accidents analyzed by Embraer, in

which performance was a factor, resulted either in runway excursions or loss of control

in-flight.

Landing Distance In almost all runways excursions, the available runway length is not sufficient for

the aircraft to stop within the runway limits as a result of the actual runway

condition, approach speed, aircraft configuration, tailwind, long flare, brake

application delay, etc.

Design regulation requires manufacturers to provide landing distance figures for

dry runways. Landing distances for wet runways are determined by simply

multiplying a factor over the dry landing distance and this multiplication is

mandated by operational requirements. Figure 4 illustrates an example of required

landing distances for a Phenom 100(12). The dry unfactored landing distance

provided by the manufacturer is determined in two parts, as shown in figure 3. The

first part corresponds the airborne distance, which is the distance between the

point in trajectory in which the aircraft is 50 ft above runway surface and the

touchdown point. The second part is the ground distance, which is the distance

from touchdown to the complete stop. The ground distance may be divided into a

transition phase, where the decelerating devices are beginning to be applied, and

a full braking phase, with the decelerating devices fully in operation.

If deviations are present in the approach, such as Vref overspeed, tailwind, aircraft

high over runway threshold and long flare, the numbers provided by the aircraft

manufacturer will no longer be valid once more runway length will be required for

the aircraft to stop within the runway limits. Such deviations are often present in

runway excursions involving single-pilot operations, and the reason is that these

operators do not have flight data monitoring programs associated with their

operations. These programs feature logics to identify certain patterns in routine

operations, with the objective to enhance flight safety by identifying potential risks

and modifying training programs accordingly.

Figure 3 - Segments of a landing - Unfactored landing distance

Figure 4 - Required landing distances for the Phenom 100

In one event, the aircraft experienced a runway overrun after landing in a wet

runway. Onboard the aircraft were four passengers and two pilots. The aircraft was

heavy, only 143 pounds (65 kilograms) below the maximum landing weight. There

had been recent rain showers over the destination airfield and marginal VFR

conditions prevailed. The pilot on the right was not type rated in the aircraft and

was handling communications and the avionics, being verbally assisted by the pilot

in command. The available landing distance was 3,600 feet (1,100 meters) and,

according to the operational manuals, for the given weight and approach flaps, a

distance of 4,124 feet (1,257 meters) would be required for a full stop, which was

greater than the available landing distance. In addition to that, the approach was

performed with a Vref overspeed of 10 knots and a 7-knot tailwind component,

which increased the required landing distance. The aircraft departed the end of the

runway at 37 knots and collided with a fence. This aircraft type provides the crew

with wind information and in the referred event, neither the pilot in command nor

the pilot in the right checked the tailwind component in the avionics.

Most part 91 operators do not have policies in place for assessing whether

sufficient landing distance exists at the time of arrival, even when conditions

(including runway, meteorological, surface, airplane weight, airplane configuration,

and planned usage of decelerating devices) are different and worse than those

planned at the time the flight was released.

In-flight performance The manufacturer also provides performance numbers for climb, cruise, descent,

holding and driftdown so the crew can plan the flight as to fuel consumption and

operational limitations considering aircraft weight, altitude and ISA deviation.

Some part 91 operators of single-pilot VLJs do not have a large background in

aviation, especially when it comes to high-performance aircraft. Some important

aspects of performance and aerodynamics may not be well comprehended by

these individuals, leading to a non-adherence to the published performance

numbers, resulting in a flight outside the certified envelope.

In one event, the aircraft experienced a loss of control in-flight at 41,000 feet.

According to the planned flight profile, the aircraft should step climb to flight level

(FL) 390 and maintain leveled flight for approximately 30 minutes before climbing

to FL410 which was the final cruising level. However, prior to takeoff, one of the

passengers did not board and the pilot in command assumed that being one

passenger lighter would allow the aircraft to climb straight to the final cruising level.

The pilot in command spent a large amount of time explaining the aircraft systems

to the person seating on the right seat, who was not type rated in the aircraft and

thus, he failed to identify the airspeed slowly decreasing to a point where the stick

pusher was activated and, subsequently, he did not react appropriately, leading to

a series of pitch oscillations until it finally stalled and entered in an uncontrolled

dive. Controlled flight was reestablished 44 seconds later, at FL295 and the aircraft

proceeded to its final destination.

Safety Recommendations Most of the single-pilot accidents have several contributing factors in common and just like in

any other type of aircraft, safety recommendations for single-pilot accidents are the most

important and valuable product of the investigation. They suggest a course of action to

improve airworthiness, operational, policy or any other safety issue identified and they can be

issued at any time during the investigation. They are based on findings of the investigation,

and may address deficiencies that are not directly related to what is ultimately determined to

be the cause or a contributing factor for the accident. The investigator must keep in mind that

repetitive patterns that cause accidents exist due to weaknesses in the aviation system and

even not being mandatory, safety recommendations is an effective way to enhance aviation

safety and break certain tendencies.

Conclusion This paper went through several subjects with the purpose to provide a manufacturer’s

perspective learned from years supporting single-pilot accidents investigations. The

complexity of these topics makes it impossible to compile all the knowledge that is desirable

to be part of the repertory of next generations of investigators in a single paper. However, I

hope this paper, which originated from Embraer’s commitment to continuously assist

investigations involving its products, may serve as a reference and contribute to better

investigations, with the purpose of making air transport safer.

Acknowledgement Writing this paper would not have been possible without the expertise and good will of all

Embraer colleagues that volunteered their time to support me.

References 1. http://www.ainonline.com/aviation-news/business-aviation/2015-06-05/accident-

analysis-single-pilot-versus-two-pilot-there-safety-advantage

2. United States, 14 CFR Part 25 - AIRWORTHINESS STANDARDS: TRANSPORT

CATEGORY AIRPLANES

3. United States, 14 CFR Part 23 - AIRWORTHINESS STANDARDS: NORMAL,

UTILITY, ACROBATIC, AND COMMUTER CATEGORY AIRPLANES

4. United States, FAA AC 25-1523 - Minimum Flight Crew

5. United States, FAA FSB Report - Cessna Aircraft Company CE-500 (Models 500,

501, 550, 551, S550, 552, 560)

6. United States, FAA AC 23-1523 - Minimum Flight Crew

7. Endsley, M.R. (1995b). Toward a theory of situation awareness in dynamic systems.

Human Factors 37(1), 32–64.

8. United States, FAA AC 120-53B - Guidance for Conducting and Use of Flight

Standardization Board Evaluations

9. Transport Canada’s Human Factors for Aviation - Basic Handbook

10. United States, NTSB, Accident Report NTSB-AAR-80-2, N15NY, 1980

11. Miller & Smith (1993). The Stress Solution: An Action Plan to Manage the Stress in

Your Life

12. Airplane Operational Manual, Embraer Phenom 100, 2016